Renewable fuse



M. J. WEST.

RENEWABLE FUSE.

APPLICATION FILED MAY20.1919.

Patented Apr; 4, 1922.

' WITNESSES: I |NVENT 0R 1' TTOBNEY:

UNITED STATES PATENT OFFICE.

IEBLE J. WEST, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO WILLIAM D. K YLE, 1O]? MILWAUKEE, WISCONSIN.

RENEWABLE FUSE.

' Application filed May 20,

To all whomz't may concern:

Be it known that I, MERLE J. VEST, a citizen of the United States, and resident of Milwaukee, in the county of Milwaukee and State of Visconsin, have invented certain new and useful Improvements in Renewable Fuses; and I do hereby declare that the following is a full, clear, and exact description thereof.

My invention relates to cut-outs for electric circuits, and particularly to cartridge fuses of the renewable or refillable type.

Although cartridge fuses of this form have been known to the trade for a considerable time, so many of them have been defective and inefficient that they have not come into such general use as to supplant the old standard non-refillable fuse. One of the principal objections to the usual refillable fuse is that upon blowing sparks and flames are liable to be thrown through unprotected cracks or openings in the wall of the fuse casing. In other words after several refillings the parts of the renewable fuses of ordinary construction become so loosened or worn that leakage'of flame is easily possible. Also with such ordinary refillable fuses there is no safeguard against careless reassembling after refilling, and thus a fuse may be replaced in the electric circuit in such con:

dition that'the fire hazard is very materially increased.

The principal objects of this invention are, therefore, to provide a protective means which-will effectively cover all possible outlets of flame whichmay occur upon blowing, and means for rendering the insertion of the fuse in the electric circuit impossible until the parts have been correctly assembled.

A further object of the invention is to provide a simply constructed means for prevent ing excessive arcing after the fusible link has blown and also to prevent any arcing whatsoever between the link attaching terminals carried by the ends of the fuse.

A still further object of my invention is to provide an indicating device which will show when a fuse has blown without first disassembling the device.

With these general objects and advantages in view, it will be seen that the invention resides in the novel features of construction, combination and arrangement of parts which will be hereinafter more particularly de- Specification of Letters Patent.

in locked position.

Patented Apr. 4,1922; 1919. Serial No. 298,478. 2

scribed and claimed and shown in the drawingin which: i V

F lgure 1 represents an elevational view of a renewable cartridge fuse, parts being broken away and in vertical section to more clearly illustrate the interior construction.

Figure 2 is a detail sectional view of one end of the fuse, and Y Figure 3 is a transverse sectional view taken substantially on the plane of the line 3-3 of Figure l. V

In the embodiment illustrated, the invention is shown associated with a cartrid e fuse of the knife blade type, but it is to %e understood that the same may be used in connection with the ordinary ferrule type, and further that various other minor changes may be made in the form and proportion and in the connection of the several parts, without departing from the principles of the invention. In all of its several forms'the fuse will consist of an inner or housing casing having an opening covered by a hinged closure whereby the fusible link may be inserted thereinto, and an outer or protective shell telescopingly engageable over the inner casing. Referring to the drawing and considering the parts of the invention in detail, it will be seen that the fuse includesa cylindrical open ended tube or fibre or other insulating and non-inflammable material which forms the major portion of a casing 1, said tube having an elongated opening formed in its wall intermediate its ends to permit access into the interior thereof after the open ends have been closed by ferrules 3 and 4 respectively. From Figures 1 and 3, it will be noticed that the opening 2 has its opposite ends rounded as at 2 and in width is substantially one-half the circumference of the tube. One longitudinal edge portion of the opening 2 has a cover 5 hinged thereto as .at 6, and the other edge portion carries 'one or more spring fingers 7 for engagement in recesses 8 in the cover for holding the same This closure 5 for the openin '2 is substantially of the same configuration as the latter and when in closed position its edge is in abuttingrrelation with the edge of said opening. his provides a very close fit between the opening and its cover and the latter has 'its outer surface flush with the corresponding surface of the casing 1.

The ferrules 3 and 4 are secured to the ends of the casing 1 by crimping as at 9, and when the fuse is of the knife blade type, they carry the contact blades 10, the latter being preferably secured to the ferrules 3 and 4 in a manner indicated in Figures 1 and 2. That is to say the ferrule 3 for instance has a slot formed in its crown to receive the blade 10 which has a shoulder 11 for engagement with the innerside of the former, the outer portion of the blade being swaged against the crown of the ferrule at a plurality of points as at 12. A reinforcing pin 13 extends through the ferrule, the adjacent portion of the casing 1 and the blade as shown.

The inner end of each blade 10 is designed to form a fuse link attaching terminal 14 to which a fusible link 15 is connected. In their preferred construction, these attaching terminals are bifurcated as at 16 and provided with threaded screw holes to receive fastening screws 17. The ends of the fusible link 15 have openings to align with the openings in the terminals when they are disposed between the furcations; the

fastening screws 17 obviously secure the link in place.

All possibility of danger through the leakage of flame between the edges of the opening 2 and its cover 5 is obviated by the addition of .an outer protective shell 18 which is of a size slightly greater than the inner casing 1 and is adapted to slide thereon. This protective shell is also formed from an open ended insulatin and noninflammable tube, one end of which is closed by a ferrule cap 19 crimped thereon as at 20, the crown of saidferrule cap having a slot to receive the adjacent contact blade 10. The opposite end of this tube has a reinforcing band 21 adapted to slide beneath a spring retaining collar 22 that is carried by the ferrule 3 and is preferably formed integrally therewith.

In assembling the protective shell on the inner casing 1, the open end of the former is slid over the ferrule 4 and the same-moved longitudinally until said reinforcing band engages the retaining collar 22 as above mentioned. When this engagement takes place the crown of the ferrule cap 19 will have come into abutting relation with the crown of the ferrule 4. Thus it will be.

seen thatthe outer protective shell 18 extends substantially throughout the length of the inner casing and completely covers the opening 2.

Ordinarily when a fuse link blows, considerable arcing occurs, this even extending to the terminal attaching members, as the parts 14, and as a result they are mutilated and refilling is rendered difficult. To overcome this difficulty I have disposed a carbon block 23 transversely of the inner casing 1 and substantially midway of the ends thereof, this block being of sufficient size to interrupt the air gap between the attaching terminals 14 to thereby prevent the flow of electricity between these parts. The

block 23 is held in position by a s ring clip 24 that has its ends 25 dispose through openings in the wall of the casing 1 and then bent laterally as particularly shown in Figure 3. The intermediate portion of the clip rests in a channel 26 formed in the block. w

As hereinbefore mentioned the present invention also includes means for indicating the condition of the fusible link 15, that is to say whether or not the same is in operating condition or has been blown. In providing such an arrangement the block 23 is provided with a central hole for the reception of a cylindrical fibre plunger 27, the inner end of which has a head 28 extended beyond the adjacent portion of the block for engagement with the fusible link 15. The opposite or outer end of the plunger is normally extended beyond the adjacent surface of the block and through a hole 29 in the wall of the'casing 1. A second hole 30 in the protective shell 18 is adapted to align with the hole 29 and disposed therein is the intermediate portion of an indicator button 31. Said button 31, is carried by the intermediate portion of a spring plate 32, the opposite ends of which are secured to the wall of the shell 18.

When the fusible link 15 is in operative condition, it bears against the head 28 of the plunger 27 and causes the outer end of the latter to force the button 31 outwardly of the shell-18 as indicated in Fig ures 1 and 3. As soon, however, as the link is blown, the tension of the spring plate 32 will be exerted to force the button inwardly so that the latter will be only slightly exposed, thus indicating to an. observer that th fuse needs refilling. Said observer may readily renew the fuse after taking the same from the switchboard or cut-out block, by slipping the protective shell 18 from off the (main 1, thereby exposing the closure 5, after w ich said closure may be opened by releasing the sprin finger 7 to permit access to the interior oft e fuse. The portions of the blown fusible link are removed by takin out the screws 17, after which a new fusi le link is inserted. The operations of assembling the several parts of the fuse are then carried out, said operations merely being the reverse of disassembling.

I claim:

1. A fuse comprising a casinghaving' an opening in its side wall, terminal contact members closing the ends of the casing, a closure plate removably disposed to close said opening, a spring collar carried by and spaced from the wall of the casing adjacent one end, a sleeve slidable around said casing to completely cover the closure plate and the edges of saidopening and having a shoulder at one end for engagement with said spring collar, and a fusible 'link consaid opening, a spring collar carried by and spaced from the wall of the casing adjacentvone end, a sleeve slidable around said casing to completely cover the closure plate and the'edges of-said opening, a cap for one end of the sleeve through which the terminal blade projects, said cap fitting against said blade to form a closure for the end of the sleeve, an annular shoulder at the other end of said sleeve for engagement with said spring collar, and a fusible link connecting the terminal contact members.

3. A fuse comprising a tubular casing, terminal contact members closing the ends of the casing, a link attaching device con nected with each of said members, a block disposed transversely of the casing and seated against one side portion of the latter,

it being spaced from the opposite side portion. said bloc-k having a channel. a spring band disposed around said block and in said channel, the opposite ends of said band being engaged with and secured to said casing. and a fusible link connecting the attaching devices. a 1 v p 4. A fuse comprising a casing having an opening through its wall. terminal contact members closing the ends of the casing, a link attaching device connected with each of said members. an anti-arcing block disposed transverselv of the casing and crossing the longitudinal plane of the attaching devices. 1 said block having an opening formed therethrough and aligned with the opening in the wall of said casing, a plunger slidable through said aligned openings, and a fusible link connecting the contact members and having its intermediate portion engaged with the inner end of said plunger whereby to hold the outer end thereof outwardly of said block. said outer end being disposed inwardly of the block when the fusible link is blown.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee, in the county of Milwaukee and State of 'isconsin.

MERLE J. WE ST. 

